Transferable values and errors about isolated-vm

[laverdet]

All instances of ExternalCopy are transferable no matter what.

If you do ref1.apply() and that function then does ref2.apply() without a try/catch in place and ref2 returns a non-transferable value then that exception would indeed throw back out to whoever invoked ref1.apply().

I suspect cross-isolate stack traces will be interesting to trace. Currently if you inspect the stack property of the error it should be the trace from where the error was first constructed. But an error could be thrown back and forth between your isolates depending on how your code is structured.

[jeromegn]

Hopefully I understand well what can and cannot be transferred. I opened #43 to make this understanding available in code.